Abstract

Spiral density waves occur across the spectrum of astrophysical discs, and have been studied from many different perspectives over the last 70 years. They’re excited by anything and everything: internal and external companions or perturbers, instabilities, vortices, disc-self-shadowing, etc., and can play important roles in the formation of gaps and rings, planet migration, accretion, and turbulence regulation and feedback.

I’ll introduce a couple of perspectives which have been particularly insightful historically, before outlining a global fully non-linear theory of these waves which Gordon Ogilvie and I developed recently, including how and when to use it, how it relates to prior work, and some immediate insights gained. I’ll focus on the problem of planet-disc interaction, comparing the theory to simulations of low-mass and very high-mass disc-embedded planets.